What is Direct linking method anyway. This method actually link the Adword campaign directly to the sales copy of the merchant. There is no other link except to the sales copy of the product. From Google Quality Score point of view, it will not give much value to readers who click the link because they will only see the sales copy. They will not received any other information except those who will persuade them to buy the product being offered. So, it will get low quality score which resulted with low position of your ad and high
However, if you can prove that you will get high click through rate, then your ad will improve its position. So, you must build a very targeted keywords and very convincing ad in order to make direct linking a successful one. I believe this is what DJK Google Shadow will teach you if you become one of their subscriber..
Want to see the proof?